The LS1 in my Monte Carlo started misfiring and running rich only in bank two all of a sudden one day and I can’t figure out why, I’ve swapped injectors, coilpacks and plugs from side to side and it didn’t follow so I can rule those out, it also has good compression in every cylinder and all of the wiring looks okay

car has never had o2’s and has driven fine for a year so isn’t that either

is it possible the ecu took a ****? There’s nothing else I can think of

 

that statement makes absolutely no sense at all.

 

I think you are confused with your o2's. You probably have had rear O2's deleted, as that is a common mod because the only thing they do is look at your cats. You probably still have front O2's, and actually I'd suggest that be the next thing to look at. Swap them side to side.

 

The car does not and has never had o2 sensors, it just runs off the maf in open loop, was tuned this way last September and has been fine since, then it started acting like this about a week ago, o2’s are not the issue